Disclosures about Fair Value of Financial Instruments - Summary of Financial Assets and Financial Liabilities Measured at Fair Value (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned	12,265	15,371
Fair Value Estimate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	3,836	2,380
Other real estate owned	335	9,149
Residential mortgage loan commitments	240	43
Impaired loans, net of reserves | Collateral Appraisal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Minimum	(3.00%)
Maximum	(8.00%)
Weighted Average	(5.50%)	(8.00%)
Other real estate owned | Collateral Appraisal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Minimum	(3.00%)
Maximum	(8.00%)
Weighted Average	(5.50%)	(8.00%)
Mortgage Loans on Real Estate | Adjusted market bid
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Inputs, Pull-Through Rate	80.00%	80.00%